This invention relates to a cleaning instrument using a premixed abrasive liquid (a liquid containing abrasive powder particles suspended therein), and more particularly to a dental cleaning instrument which dispenses a flow of air with the premixed abrasive liquid.
Various devices are known for cleaning teeth using a flow of air with powder particles therein. In some of these known devices, a flow of water (or other liquid) is combined with air and dry powder particles. The dry powder particles are mixed with the liquid and act as abrasive particles which clean the teeth when the liquid flow containing the powder particles is directed onto the surface of the teeth. The known devices are generally in the form of a hand piece which has a nozzle for directing a liquid jet, such as a water jet, containing the abrasive powder, onto the surface of the teeth to be cleaned.
The known devices use a supply of dry powder particles and have several difficulties and disadvantages. One such disadvantage is that in the known devices, the supply of dry powder particles (abrasive particles) tend to cake up in the instrument, thereby making cleaning extremely difficult. The "caking up" of the powder particles is a particular problem when the powder particles are exposed to high humidity conditions. In this case, clogging of the passages sometimes occurs. When the powder particles cake up or clog the device, it is extremely difficult to clean the instrument. In most cases, the instrument is not sufficiently dismantlable, so that cleaning becomes even more difficult.
Another disadvantage of the prior art is that it is very difficult to control the powder particle flow in the dry powder systems presently known in the art. That is, the powder flow becomes non-uniform, and the concentration of abrasive particles varies during use, and the volume of flow tends to vary during use. This is very disadvantageous since, when using the device to clean teeth, sensitive gum tissue may be damaged if the flow and concentration of powder particles is not accurately and uniformly controlled.
In some prior art devices, the dry powder container has been mounted separate from the hand piece in attempt to obtain easier and more accurate flow control. However, this arrangement still does not eliminate the caking up or clogging problem, and the flow of powder particles is still not as accurately controlable as desired.
The object of the present invention is to provide a dental cleaning apparatus for jetting a flow of air and powder particles onto the surface of teeth to be cleaned, in which caking up of the powder particles is not a problem, cleaning of the device is particularly easy and control of particle flow is accurately controlable. A further object of the invention is to provide such a device which is easily and quickly refillable. A still further object of the invention is to provide a compact relatively simple and inexpensive, dismantable, and easily cleaned apparatus having the foregoing advantages.